A 78° Extended Reach Well in the Gulf of Mexico, Eugene Island 326 No. A-6

Abstract

ABSTRACT This paper describes the successful drilling & completion of Forest oil Corporation's OCS-G-5518 No. A-6, Eugene Island Block 326. The subject well was drilled as a 79 deg high angle extended reach well (ERW) from an existing production platform in the adjacent Eugene Island Block 325. The purpose was to establish production from a shallow sand located at a depth of 2300 'TVD(701M) at a reservoir take point located 7000' (2134M) from the existing platform. The paper focuses on the engineering aspect of the well plan and the operational problems that were encountered. The final results indicate that a shallow extended reach well with an MD/TVD ratio of 3.1:1 can be successfully drilled and completed in the Gulf of Mexico. The techniques used and the lessons learned can be applied to any area with modifications for that particular drilling area. Existing platforms can be used to cut cost and to protect adjacent leases as "Held By Production". New platform placement can take into consideration the drilling of extended reach wells. INTRODUCTION Forest oil Corporation (FOC) drilled a discovery well, OCS-G-5517 No.3, in Eugene Island Blk 325 in November of 1987. The well was a straight hole drilled to 6100'MD/TVD(1859 M). A six well drilling template was then placed over the No. 3 well and several additional wells were drilled using a jackup drilling rig in 255'(78 M) of water. Another discovery well, OCS-G5518 No.2, was drilled in Eugene Island Blk 326 in March of 1988 to 4939'MD/TVD(1505 M). This well found a productive sand at 2300'(701M). A platform was then set over the drilling template in E.I. Blk 325 and tieback and completion operations were begun. Figure 1 shows the location of Eugene Island Blocks 325 and 326. It became necessary to establish production from E.L Blk 326 and "HOLD IT BY PRODUCTION" in an economical manner. Several options were considered.Set a minimum offshore structure (MOSS) over the existing discovery well in Block 326, install test facilities only, and flow to the existing platform in Block 325 for processing.Perform a subsea completion flowing to the existing platform in Block 325 for processing.Drill and complete an ERW from the existing platform in Block 325. The cost analysis showed that options 2. and 3. would cost approximately the same and that option 1. would cost twice as much as the other two. Because of the cost and because of the mechanical problems often associated with option 2., option 3. was chosen. The basic directional plan was as follows.Build at a rate of 6 deg/100' from the surface to a maximum angle of 77 deg 19 min at 1389'MD(423M)/1000'TVD(305M).Hold the angle of 77 deg 19' to a total depth of 7169'MD (2185M)/2300'TVD (701M). This plan resulted in an MD/TVD ratio of 3:1:1. Figure 2 shows the spider plot of the wells drilled from the Eugene Island Block 325 production platform.